4-1
Memory and I/O Spaces
Memory and I/O Spaces
This chapter describes the ’C2xx memory configuration options and the ad-
dress maps of the individual ’C2xx devices. It also illustrates typical ways of
interfacing the ’C2xx with external memory and external input/output (I/O)
devices.
Each ’C2xx device has a 16-bit address line that accesses four individually se-
lectable spaces (224K words total):
-
A 64K-word program space
-
A 64K-word local data space
-
A 32K-word global data space
-
A 64K-word I/O space
Also available on select ’C2xx devices are an on-chip boot loader and a HOLD
operation. The on-chip boot loader allows a ’C2xx to boot software from an
8-bit external ROM to a 16-bit external RAM at reset. The HOLD operation al-
lows a ’C2xx to give external devices direct memory access to external pro-
gram, data, and I/O spaces.
Topic
Page
4.1
Overview of the Memory and I/O Spaces
4-2
. . . . . . . . . . . . . . . . . . . . . . . .
4.2
Program Memory
4-5
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3
Local Data Memory
4-7
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4
Global Data Memory
4-11
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5
Boot Loader
4-14
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6
I/O Space
4-23
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7
Direct Memory Access Using the HOLD Operation
4-27
. . . . . . . . . . . . . .
4.8
Device-Specific Information
4-31
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 4
